Modelling uncertainty in natural resource analysis using fuzzy sets and Monte Carlo simulation: slope stability prediction

The techniques of fuzzy logic and Monte Carlo simulation are combined to address two incompatible types of uncertainty present in most natural resource data: thematic classification uncertainty and variance in unclassified continuously distributed data. The resultant model of uncertainty is applied to an infinite slope stability model using data from Louise Island, British Columbia. Results are summarized so as to answer forestry decision support queries. The proposed model of uncertainty in resource data analysis is found to have utility in combining different types of uncertainty, and efficiently utilizing available metadata. Integration of uncertainty data models with visualization tools is considered a necessary prerequisite to effective implementation in decision support systems.     

Bulk chemistry of Saharan shergottite Dar al Gani 476

Abstract— We report on major and trace element analyses obtained by, respectively, inductively coupled plasma‐atomic emission spectrometry (ICP‐AES) and inductively coupled plasma‐mass spectrometry (ICP‐MS) of three different aliquots of the new Saharan shergottite Dar al Gani (DaG) 476. The new analyses are in excellent agreement with previous data (Zipfel et al., 2000). Ba, Sr and U abundances, together with the presence of carbonate, suggest that the sample has been significantly weathered. Three rare earth element (REE) patterns (normalized to CI) determined on three different aliquots of the sample all show similar shapes. The heavy REEs are flat with a slight depletion at the heavy end and a strong depletion from Dy to Pr. All of the patterns display an upturn to La which we interpret as being caused by the introduction of a terrestrial component. Taking the terrestrial contamination into account, this study demonstrates that DaG 476 is one of the most depleted of the shergottites, and, just like Queen Alexandra Range (QUE) 94201 (Dreibus et al., 1996), displays very low Zr/Hf ratios. It appears that the Zr/Hf ratios of shergottites are not uniform, and have been significantly fractionated by martian mantle processes.     

The effects of space weathering on Apollo 17 mare soils: Petrographie and chemical characterization

Abstract— The lunar soil characterization consortium, a group of lunar‐sample and remote‐sensing scientists, has undertaken the extensive task of characterization of the finest fractions of lunar soils, with respect to their mineralogical and chemical makeup. These compositional data form the basis for integration and modeling with the reflectance spectra of these same soil fractions. This endeavor is aimed at deciphering the effects of space weathering of soils on airless bodies with quantification of the links between remotely sensed reflectance spectra and composition. A beneficial byproduct is an understanding of the complexities involved in the formation of lunar soil. Several significant findings have been documented in the study of the <45 μm size fractions of selected Apollo 17 mare soils. As grain size decreases, the abundance of agglutinitic glass increases, as does the plagioclase, whereas the other minerals decrease. The composition of the agglutinitic glass is relatively constant for all size fractions, being more feldspathic than any of the bulk compositions; notably, TiO₂ is substantially depleted in the agglutinitic glass. However, as grain size decreases, the bulk composition of each size fraction continuously changes, becoming more Al‐rich and Fe‐poor, and approaches the composition of the agglutinitic glasses. Between the smallest grain sizes (10–20 and < 10 μm), the I_S/FeO values (amount of total iron present as nanophase Fe⁰) increase by greater than 100% (>2x), whereas the abundance of agglutinitic glass increases by only 10–15%. This is evidence for a large contribution from surface‐correlated nanophase Fe⁰ to the I_S/FeO values, particularly in the <10 μm size fraction. The surface nanophase Fe⁰ is present largely as vapor‐deposited patinas on the surfaces of almost every particle of the mature soils, and to a lesser degree for the immature soils (Keller et al., 1999a). It is reasoned that the vapor‐deposited patinas may have far greater effects upon reflectance spectra of mare soils than the agglutinitic Fe⁰.     

The optical properties of the finest fraction of lunar soil: Implications for space weathering

Abstract— The fine fraction of lunar soils (<45 μm) dominates the optical properties of the bulk soil. Definite trends can be seen in optical properties of size separates with decreasing particle size: diminished spectral contrast and a steeper continuum slope. These trends are related to space weathering processes and their affects on different size fractions. The finest fraction (defined here as the <10 μm fraction) appears to be enriched in weathering products relative to the larger size fractions, as would be expected for surface correlated processes. This <10 μm fraction tends to exhibit very little spectral contrast, often with no distinguishable ferrous iron absorption bands. Additionally, the finest fractions of highland soils are observed to have very different spectral properties than the equivalent fraction of mare soils when compared with larger size fractions. The spectra of the finest fraction of feldspathic soils flatten at longer wavelengths, whereas those of the finest fraction of basaltic soils continue to increase in a steep, almost linear fashion. This compositional distinction is due to differences in the total amount of nanophase iron that accumulates in space weathering products. Such ground‐truth information derived from the <10 μm fraction of lunar soils provides valuable insight into optical properties to be expected in other space weathering environments such as the asteroids and Mercury.     

Kaolin: a servant of humanity

Kaolinite, an aristocrat of minerals, serves as the medium on which is printed the records of scholarly human culture from the oldest known to the present. It also serves as a refractory to confine ultra–high temperatures and protect furnaces used in modern industry and technology. Produced by reaction between rigid igneous silicates and physically yielding but chemically potent water, kaolin crystals reveal a graphic story, shown in scanning electron micrographs, of most diverse properties, geneses and potential applications.     

A Quaternary Solution Model for White Micas Based on Natural Coexisting Phengite-Paragonite Pairs

A thermodynamic model for the quaternary white mica solid solutionwith end-members muscovite–Mg-celadonite–paragonite–Fe-celadonite(Ms–MgCel–Pg–FeCel) is presented. The interactionenergies for the MgCel–Pg join, the FeCel–Pg joinand the ternary interactions were obtained from natural coexistingphengite–paragonite pairs. Phengite–paragonite pairswere selected based on the criteria that their chemical compositionsmay be represented as a linear combination of the model end-membercompositions and that the respective formation conditions (350–650°C,4–21 kbar) are accurately known. Previously publishedexcess free energy expressions were used for the Ms–Pg,Ms–MgCel and Ms–FeCel binaries. The suggested mixingmodel was tested by calculating multicomponent equilibrium phasediagrams. This proved to be particularly well suited to reproducecompositional variations of white micas from amphibolite-faciesmetapelites. KEY WORDS: white mica; solution model; equilibrium phase diagrams     

Phase Relations and Chemical Composition of Phengite and Paragonite in Pelitic Schists During Decompression: a Case Study from the Monte Rosa Nappe and Camughera-Moncucco Unit, Western Alps

The metamorphic evolution of metapelites from the eastern partof the Monte Rosa nappe and the Camughera–Moncucco unit,both situated in the upper Penninic units SW of the Simplonline, were investigated using microstructural relationshipsand equilibrium phase diagrams. The units under considerationexperienced pre-Alpine amphibolite-facies conditions and underwenta complex metamorphic evolution during the Alpine orogeny. Peakpressures during an early Alpine high-pressure stage of 12·5–16kbar were similar in the Monte Rosa nappe and Camughera–Moncuccounit. A pronounced thermal gradient is indicated during decompressionleading to an amphibolite-facies overprint, as the decompressionpaths went through the chlorite, biotite and plagioclase stabilityfields in most of the Monte Rosa nappe, through the staurolitefield in the easternmost Monte Rosa nappe and in the Camughera–Moncuccounit, and through the sillimanite field in the easternmost Camughera–Moncuccounit. In high-Al metapelites the initial formation of stauroliteis related to continuous paragonite breakdown and associatedformation of biotite. In the course of this reaction phengitebecomes successively sodium enriched. In low-Al metapelites,in contrast, the initial staurolite formation occurs via thecontinuous breakdown of sodium-rich phengite. In both low- andhigh-Al metapelites the largest volume of staurolite is formedduring the continuous breakdown of sodium-rich phengite belowP–T conditions of about 9·5 kbar at 600–650°C.During this reaction phengite becomes successively potassiumenriched as sodium from phengite is used to form the albitecomponent in plagioclase. For ‘normal’ pelitic chemistries,phengite becomes Na enriched during decompression through thebreakdown of paragonite along a near-isothermal decompressionpath. The Na content in phengite reaches its maximum when paragoniteis entirely consumed. During further decompression the paragonitecomponent in phengite decreases again because Na is preferentiallyincorporated into the albite component of plagioclase. KEY WORDS: metapelites; white mica; high pressure; equilibrium diagrams; Western Alps     

The differentiation of eucrites: The role of in situ crystallization

Abstract— We report on major and trace element analyses of 17 eucrites, including three cumulate eucrites (Binda, Moore County, and Serra de Magé), determined by, respectively, inductively‐coupled plasma atomic emission spectrometry and inductively‐coupled plasma mass spectrometry. The results obtained for Binda and Moore County are consistent with the model of Treiman (1997) for the formation of cumulate eucrites, which holds that these meteorites were produced from a eucritic melt. Our sample of Serra de Magé contains unusually large amounts of pyroxene and probably an accessory phase rich in heavy rare earth elements and is therefore not representative of this eucrite as known from literature data. Our results for the noncumulate eucrites Bereba, Bouvante, Cachari, Caldera, Camel Donga, Ibitira, Jonzac, Juvinas, Lakangaon, Millbillillie, Padvarninkai, Pasamonte, Sioux County, and Stannern are in good agreement with literature data. The observed decoupling between major and trace elements for noncumulate eucrites can be explained by in situ crystallization during the differentiation of an asteroidal magma ocean. This model can further account for both the Nuevo Laredo and the Stannern trends but has as a consequence that none of the analyzed eucrites represents a primary melt.     

Trace Element and Sr, Nd, Pb and O Isotope Variations in Medium-K and High-K Volcanic Rocks from Merapi Volcano, Central Java, Indonesia: Evidence for the Involvement of Subducted Sediments in Sunda Arc Magma Genesis

Merapi volcano (Central Java), located within the Quaternaryvolcanic front of the Sunda arc, is one of the most active volcanoesof the Indonesian archipelago. During the Holocene, Merapi eruptedbasalts and basaltic andesites of medium-K affinity during itsearlier stages of activity and high-K compositions over thepast